During a grinding, polishing or similar operation performed on a workpiece, it is oftentimes critical that the temperature generated between the workpiece surface and the tool surface in contact therewith be accurately monitored and not exceed a predetermined amount. Where such temperatures are not properly controlled, important surface characteristics (e.g., hardness, wear-life, appearance and contour of the workpiece and/or the tool) may be seriously impaired.
In the past, the temperature control in such a situation depended to a substantial extent upon the skill and experience of the operator, and upon the type, volume, temperature and flow direction of the coolant circulated across the workpiece and tool surfaces. Various apparatus have heretofore been provided in an effort to attain better surface temperature control; however, because of certain inherent design features such apparatus has been beset with one or more of the following shortcomings: (a) the thermal sensing means or the detecting means were exposed to splash from the circulating coolant and thus, the accuracy of such means was impaired; (b) the location of the thermal sensing means on the tool surface caused unbalancing forces or stresses to develop within the tool thereby seriously shortening wear life; (c) the apparatus required an inordinate amount of service and maintenance; (d) the apparatus embodied numerous, costly and fragile components which were highly susceptible to malfunction; and (e) the apparatus was incapable of being utilized in conjunction with a variety of machining tools.